The present invention relates generally to an apparatus for signaling pedestrian traffic at intersections and, in particular, to an apparatus for prompting pedestrians using crosswalks to look for turning vehicles.
It is general knowledge that turning vehicles kill and injure many pedestrians crossing with the walk signal at signalized intersections. Optical signals, in particular a white pictograph of a walking pedestrian or a red or orange pictograph of an upraised hand, are used to signal whether crossing the road is authorized or prohibited and are in widespread use. In addition, the U.S. Pat. No. 5,241,307 shows a push button operated device which immediately generates red and green figurines when the push button is actuated by a pedestrian and generates an audio message upon activation of the push button for a predetermined time. The audio message prompts blind persons as to whether crossing the road is authorized or prohibited. Some evidence exists that signals indicating that crossing is authorized can give pedestrians a false sense of security and may contribute to vehicle/pedestrian collisions in signalized intersections by decreasing pedestrian visual and auditory observing behavior.
One way to prompt pedestrians to listen and watch for turning vehicles during the time when crossing is authorized is the use of signs located next to the walk button requesting that they be alert to turning vehicles. There are several drawbacks to this approach. One drawback is that not all crosswalks require that a walk button be pressed and, even if it is required, the person can press the button without reading the sign.
No device is known, however, for using a voice and or animated visual message to prompt pedestrians to look for turning vehicles. The present invention has been designed to correct this problem. A variation to this device can also be used to prompt pedestrians to watch for vehicles passing vehicles that have yielded for them at unsignalized marked crosswalks.
Traffic lights have been used for a long time and, they, like automobiles, have gone from being an oddity and a rarity, at the beginning of this century, to being a virtual necessity. At the same time traffic lights have become increasingly complex. Integrating a traffic light into an entire traffic control system has necessitated interconnecting traffic signals electronically to properly coordinate vehicular and pedestrian traffic at specific intersections as well as to properly coordinate vehicle traffic between intersections.
Advertising displays directed to motorists to promote merchants' products and services are, of course, also very common, usually in the form of highway billboards, signage along streets, and store front displays. There are some very good reasons to combine advertising displays with traffic signals. For example, traffic control signals are usually placed at intersections where there is a high volume of vehicular traffic, so advertising at those same intersections would get exposed to many people, usually at times when the people can do little else other than to drive or ride in the vehicle. Revenues from the rental of such advertising space on traffic signals could be put to good use by local governments for road and street improvements or other desirable community improvements or expenditures. There may also be some very real benefits in providing advertising displays to occupy drivers' minds and attentions to decrease boredom and irritability while they wait at red lights or are stalled in congested traffic.
Unfortunately, there are also some safety concerns, as well as practical considerations, that have thus far prevented any widespread or even minimal general use of advertising displays in conjunction with traffic signals. One of the most significant safety problems is that the advertising displays could tend to divert drivers' attentions from the traffic control signals and from observing surrounding vehicular and pedestrian traffic at busy intersections when their utmost attention to their driving is needed to avoid traffic congestion and even possible accidents. Also, the physical locations of many traffic signals adjacent, and often over, busy streets and walkways presents a problem in changing the advertising displays during normal business hours without impeding the flow of traffic.
There are a few examples of earlier attempts to combine advertising displays with traffic signals, which have never attained any significant use, probably because they did not solve the safety and practical problems discussed above. For example, the U.S. Pat. No. 1,662,348 shows a large, framed, box-like mounting structure that contains both a set of red, amber, and green traffic signal lights and an illuminated advertising display. The advertising display portion of this apparatus includes a semi-transparent surface mask or screen having advertising printed thereon along with a set of back lights to illuminate the advertising mask or screen from behind. Stricker apparently tried to minimize the problem of diverting drivers' attentions from the stop, go, and caution messages intended to be conveyed by the conventional red, green, and amber traffic lights by providing corresponding red, green, and amber back lighting for illuminating his advertising displays. Unfortunately, such color-coordinated backlighting still presented the advertising to the drivers at all times.
While the U.S. Pat. No. 2,503,574, shows an advertising display that is positioned in sidewalk curbs rather than adjacent the vehicular traffic control lights, such a display presents the same kind of problem to both pedestrians and to drivers who are in a position to see the display. In fact, this device really exacerbates the safety problem, because it combines and makes the "STOP" and "GO" signals integral parts with the advertising message. Such a combination could actually confuse people and camouflage the intended traffic control message in the advertising message, thus, losing, or at least diluting, the crisp significance of the traffic control message.
The U.S. Pat. No. 5,150,116 shows a traffic light timed advertising center including an advertising display device, such as an electronic message center or other visual display device for displaying alpha-numeric and symbolic advertising messages, in which the advertising messages can be made selectively visible and invisible to drivers, is positioned adjacent a traffic control signal device having alternative signal phases for sequentially stopping and permitting the flow of traffic. A display control device, including an electronic control signal, coordinates the advertising display device with the traffic control signal device to make the advertising message invisible to drivers at selected times, particularly during transitions of the traffic control signal device from one signal phase to another, during a particular phase, and for predetermined time intervals before or after the transition from one phase to another, as desired or appropriate to display the advertising message only during times of the traffic control signal device phases when drivers' attentions to the advertising message will not adversely affect the drivers' attentions to required driving functions.
As stated above, optical signaling for pedestrians, in particular with the help of green or red figurines indicating whether the crossing of a road is authorized or forbidden, is well known today. In some countries, the figurines are replaced by the indications "Walk" and "Don't Walk". In order that blind persons may benefit from a sound signaling, the latter must include a sound device. Such a device is shown in the French Patent Application FR-A-2 627 882. It includes a loud speaker activated by an ultrasonic receiver which is arranged for receiving an ultrasonic request signal transmitted from a remote control housing with a push button. When this remote control housing push button is activated, the ultrasonic request signal is stored while waiting for a green figurine for pedestrians to appear, which launches the transmission of an audible message.
Such a device, of course, brings the advantage that the sound signaling is operated only upon request and not continuously, which could trouble the neighborhood because of an infinite repetition of the same crossing authorization and forbidding messages. On the other hand, this device has the disadvantage of being relatively expensive, especially if each blind person is provided with his own remote control housing. In addition, it seems difficult for a single four road crossing or a more complex one to forecast which crossing the pedestrian intends to undertake. The situation will be even more complicated if several blind persons simultaneously arrive at the same crossing.
Sound signaling and optical signaling at a crosswalk both can be activated by a single push button as shown in the U.S. Pat. No. 5,241,307. An activation of optical signaling, such as green and red figurines is immediate, whereas the transmission of a sound message authorizing or forbidding a crossing is activated only when the pedestrian pushes the button for a predetermined time. The generation device for sound signals is controlled by a microprocessor including logic and analog inputs and outputs, the messages being stored in digital form and transmitted according to the ADPCM method.
Pedestrian traffic as well as automobile traffic makes use of intersections in urban and suburban streets. As pedestrians travel from one location in a city to another, they are faced with many intersections which must be crossed. In order to assist the pedestrians in crossing safely, the familiar "WALK" and "DON'T WALK" signs are linked to standard motor-traffic controls. This allows pedestrians to, ideally, cross with, rather than against, the flow of automobile traffic. While these controls, i.e. the "WALK" and "DON'T WALK" signs, warn pedestrian traffic of the safest opportunity to cross the intersection, they do not prevent a pedestrian from crossing against the light, i.e. entering the intersection when oncoming traffic has a "green light".
Also many urban areas and resort areas that have an especially heavy flow of pedestrian traffic have non-intersection crosswalks, i.e. crosswalks between intersections in which pedestrians always have the right of way. There are presently no warning light systems that warn oncoming traffic that a pedestrian is attempting to cross against the light or has entered a non-intersection crosswalk and is presently in the crosswalk. This need is most acute during periods of poor visibility when an alert driver would experience difficulty in spotting pedestrians.
The U.S. Pat. No. 5,406,276 shows a crosswalk warning light system for warning drivers that a pedestrian has entered a crosswalk by shining a light, preferably a laser, having a beam parallel to the crosswalk. The crosswalk warning light system detects a pedestrian entering the crosswalk and activates a light that is aimed across the intersection, thus the driver sees this beam of light, which is projected across the intersection and is warned of the presence of a pedestrian in the crosswalk. The crosswalk warning light system is timed so as to deactivate the light after a predetermined interval of time. In the preferred embodiment, a first and an adjacent laser are spaced apart a distance substantially the width of the crosswalk, provide parallel beams of light on each side of the crosswalk. Also in the preferred embodiment, a second laser, disposed at the opposite end of the crosswalk, provides a second beam of light, aimed substantially co-linearly with the first. This allows at least a partial beam of light at each end of the crosswalk in the event a pedestrian blocks the first laser beam.
Obviously, the "WALK" indication means that there may or may not be possible conflict of pedestrians with turning vehicles. However, much evidence suggests that pedestrians do not consistently look for conflicts with turning vehicles. For example, the over representation of left turning vehicles in pedestrian collisions in crosswalks at signalized intersections has been carefully documented by researchers (Habib, 1980; Quaye, Leden and Hauer, 1993). Quaye et al. speculated that these types of crashes may be related to the low level of observing behavior exhibited by pedestrians using crosswalks with traffic and pedestrian signals.
Van Houten and Malenfant (1995) found that serious motor vehicle pedestrian conflicts occur:
infrequently for vehicles turning right on red, PA1 at a moderate frequency for vehicles turning right on green, and PA1 at a very high frequency for vehicles turning left on green.
In fact, conflicts with vehicles turning left on green were more numerous than conflicts with vehicles turning right on green and right on red combined. These data are in accord with the data published by others showing that left turning vehicles are over represented in pedestrian collisions at crosswalks. When Van Houten and Malenfant examined pedestrian observing behavior relative to the location of turning vehicles, they found the percentage of pedestrians looking for turning vehicles was highest for vehicles starting their turn ahead of the pedestrian, lower for vehicles starting their turn beside the pedestrian, and lowest for vehicles starting their mm behind the pedestrian. These data showed that there is a strong inverse relationship between the occurrence of motor vehicle pedestrian conflicts and the level of pedestrian observing behavior.
Van Houten and Malenfant also found that signs requesting pedestrians to look for turning vehicles erected next to the pedestrian signal head, or a similar message painted in the crosswalk, produced enduring increases in the percentage of pedestrians looking for all threats and almost eliminated conflicts between pedestrians and turning vehicles. Similar reductions were also reported by Van Houten, Malenfant, Van Houten, and Retting (1995) using a digitally recorded verbal message played at the start of the "WALK" phase prompting pedestrians to look for mining vehicles. The reductions in conflict frequency reported in these studies takes on considerable significance given the high correlation between this type of conflict and the incidence of pedestrian crashes (Lord, 1994).
Although the use of paint and signs prompting pedestrians to look for turning vehicles has been shown to be effective in reducing conflicts with turning vehicles, and may be warranted and appropriate at certain intersections, the wide scale implementation and maintenance of these prompts would increase the workload of highway engineers, would lead to the proliferation of signs, and would prove costly in the long run.